1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * arch/arm/kernel/sys_oabi-compat.c 4 * 5 * Compatibility wrappers for syscalls that are used from 6 * old ABI user space binaries with an EABI kernel. 7 * 8 * Author: Nicolas Pitre 9 * Created: Oct 7, 2005 10 * Copyright: MontaVista Software, Inc. 11 */ 12 13 /* 14 * The legacy ABI and the new ARM EABI have different rules making some 15 * syscalls incompatible especially with structure arguments. 16 * Most notably, Eabi says 64-bit members should be 64-bit aligned instead of 17 * simply word aligned. EABI also pads structures to the size of the largest 18 * member it contains instead of the invariant 32-bit. 19 * 20 * The following syscalls are affected: 21 * 22 * sys_stat64: 23 * sys_lstat64: 24 * sys_fstat64: 25 * sys_fstatat64: 26 * 27 * struct stat64 has different sizes and some members are shifted 28 * Compatibility wrappers are needed for them and provided below. 29 * 30 * sys_fcntl64: 31 * 32 * struct flock64 has different sizes and some members are shifted 33 * A compatibility wrapper is needed and provided below. 34 * 35 * sys_statfs64: 36 * sys_fstatfs64: 37 * 38 * struct statfs64 has extra padding with EABI growing its size from 39 * 84 to 88. This struct is now __attribute__((packed,aligned(4))) 40 * with a small assembly wrapper to force the sz argument to 84 if it is 88 41 * to avoid copying the extra padding over user space unexpecting it. 42 * 43 * sys_newuname: 44 * 45 * struct new_utsname has no padding with EABI. No problem there. 46 * 47 * sys_epoll_ctl: 48 * sys_epoll_wait: 49 * 50 * struct epoll_event has its second member shifted also affecting the 51 * structure size. Compatibility wrappers are needed and provided below. 52 * 53 * sys_ipc: 54 * sys_semop: 55 * sys_semtimedop: 56 * 57 * struct sembuf loses its padding with EABI. Since arrays of them are 58 * used they have to be copyed to remove the padding. Compatibility wrappers 59 * provided below. 60 * 61 * sys_bind: 62 * sys_connect: 63 * sys_sendmsg: 64 * sys_sendto: 65 * sys_socketcall: 66 * 67 * struct sockaddr_un loses its padding with EABI. Since the size of the 68 * structure is used as a validation test in unix_mkname(), we need to 69 * change the length argument to 110 whenever it is 112. Compatibility 70 * wrappers provided below. 71 */ 72 73 #include <linux/syscalls.h> 74 #include <linux/errno.h> 75 #include <linux/fs.h> 76 #include <linux/cred.h> 77 #include <linux/fcntl.h> 78 #include <linux/eventpoll.h> 79 #include <linux/sem.h> 80 #include <linux/socket.h> 81 #include <linux/net.h> 82 #include <linux/ipc.h> 83 #include <linux/uaccess.h> 84 #include <linux/slab.h> 85 86 struct oldabi_stat64 { 87 unsigned long long st_dev; 88 unsigned int __pad1; 89 unsigned long __st_ino; 90 unsigned int st_mode; 91 unsigned int st_nlink; 92 93 unsigned long st_uid; 94 unsigned long st_gid; 95 96 unsigned long long st_rdev; 97 unsigned int __pad2; 98 99 long long st_size; 100 unsigned long st_blksize; 101 unsigned long long st_blocks; 102 103 unsigned long st_atime; 104 unsigned long st_atime_nsec; 105 106 unsigned long st_mtime; 107 unsigned long st_mtime_nsec; 108 109 unsigned long st_ctime; 110 unsigned long st_ctime_nsec; 111 112 unsigned long long st_ino; 113 } __attribute__ ((packed,aligned(4))); 114 115 static long cp_oldabi_stat64(struct kstat *stat, 116 struct oldabi_stat64 __user *statbuf) 117 { 118 struct oldabi_stat64 tmp; 119 120 tmp.st_dev = huge_encode_dev(stat->dev); 121 tmp.__pad1 = 0; 122 tmp.__st_ino = stat->ino; 123 tmp.st_mode = stat->mode; 124 tmp.st_nlink = stat->nlink; 125 tmp.st_uid = from_kuid_munged(current_user_ns(), stat->uid); 126 tmp.st_gid = from_kgid_munged(current_user_ns(), stat->gid); 127 tmp.st_rdev = huge_encode_dev(stat->rdev); 128 tmp.st_size = stat->size; 129 tmp.st_blocks = stat->blocks; 130 tmp.__pad2 = 0; 131 tmp.st_blksize = stat->blksize; 132 tmp.st_atime = stat->atime.tv_sec; 133 tmp.st_atime_nsec = stat->atime.tv_nsec; 134 tmp.st_mtime = stat->mtime.tv_sec; 135 tmp.st_mtime_nsec = stat->mtime.tv_nsec; 136 tmp.st_ctime = stat->ctime.tv_sec; 137 tmp.st_ctime_nsec = stat->ctime.tv_nsec; 138 tmp.st_ino = stat->ino; 139 return copy_to_user(statbuf,&tmp,sizeof(tmp)) ? -EFAULT : 0; 140 } 141 142 asmlinkage long sys_oabi_stat64(const char __user * filename, 143 struct oldabi_stat64 __user * statbuf) 144 { 145 struct kstat stat; 146 int error = vfs_stat(filename, &stat); 147 if (!error) 148 error = cp_oldabi_stat64(&stat, statbuf); 149 return error; 150 } 151 152 asmlinkage long sys_oabi_lstat64(const char __user * filename, 153 struct oldabi_stat64 __user * statbuf) 154 { 155 struct kstat stat; 156 int error = vfs_lstat(filename, &stat); 157 if (!error) 158 error = cp_oldabi_stat64(&stat, statbuf); 159 return error; 160 } 161 162 asmlinkage long sys_oabi_fstat64(unsigned long fd, 163 struct oldabi_stat64 __user * statbuf) 164 { 165 struct kstat stat; 166 int error = vfs_fstat(fd, &stat); 167 if (!error) 168 error = cp_oldabi_stat64(&stat, statbuf); 169 return error; 170 } 171 172 asmlinkage long sys_oabi_fstatat64(int dfd, 173 const char __user *filename, 174 struct oldabi_stat64 __user *statbuf, 175 int flag) 176 { 177 struct kstat stat; 178 int error; 179 180 error = vfs_fstatat(dfd, filename, &stat, flag); 181 if (error) 182 return error; 183 return cp_oldabi_stat64(&stat, statbuf); 184 } 185 186 struct oabi_flock64 { 187 short l_type; 188 short l_whence; 189 loff_t l_start; 190 loff_t l_len; 191 pid_t l_pid; 192 } __attribute__ ((packed,aligned(4))); 193 194 static long do_locks(unsigned int fd, unsigned int cmd, 195 unsigned long arg) 196 { 197 struct flock64 kernel; 198 struct oabi_flock64 user; 199 mm_segment_t fs; 200 long ret; 201 202 if (copy_from_user(&user, (struct oabi_flock64 __user *)arg, 203 sizeof(user))) 204 return -EFAULT; 205 kernel.l_type = user.l_type; 206 kernel.l_whence = user.l_whence; 207 kernel.l_start = user.l_start; 208 kernel.l_len = user.l_len; 209 kernel.l_pid = user.l_pid; 210 211 fs = get_fs(); 212 set_fs(KERNEL_DS); 213 ret = sys_fcntl64(fd, cmd, (unsigned long)&kernel); 214 set_fs(fs); 215 216 if (!ret && (cmd == F_GETLK64 || cmd == F_OFD_GETLK)) { 217 user.l_type = kernel.l_type; 218 user.l_whence = kernel.l_whence; 219 user.l_start = kernel.l_start; 220 user.l_len = kernel.l_len; 221 user.l_pid = kernel.l_pid; 222 if (copy_to_user((struct oabi_flock64 __user *)arg, 223 &user, sizeof(user))) 224 ret = -EFAULT; 225 } 226 return ret; 227 } 228 229 asmlinkage long sys_oabi_fcntl64(unsigned int fd, unsigned int cmd, 230 unsigned long arg) 231 { 232 switch (cmd) { 233 case F_OFD_GETLK: 234 case F_OFD_SETLK: 235 case F_OFD_SETLKW: 236 case F_GETLK64: 237 case F_SETLK64: 238 case F_SETLKW64: 239 return do_locks(fd, cmd, arg); 240 241 default: 242 return sys_fcntl64(fd, cmd, arg); 243 } 244 } 245 246 struct oabi_epoll_event { 247 __u32 events; 248 __u64 data; 249 } __attribute__ ((packed,aligned(4))); 250 251 #ifdef CONFIG_EPOLL 252 asmlinkage long sys_oabi_epoll_ctl(int epfd, int op, int fd, 253 struct oabi_epoll_event __user *event) 254 { 255 struct oabi_epoll_event user; 256 struct epoll_event kernel; 257 258 if (ep_op_has_event(op) && 259 copy_from_user(&user, event, sizeof(user))) 260 return -EFAULT; 261 262 kernel.events = user.events; 263 kernel.data = user.data; 264 265 return do_epoll_ctl(epfd, op, fd, &kernel, false); 266 } 267 268 asmlinkage long sys_oabi_epoll_wait(int epfd, 269 struct oabi_epoll_event __user *events, 270 int maxevents, int timeout) 271 { 272 struct epoll_event *kbuf; 273 struct oabi_epoll_event e; 274 mm_segment_t fs; 275 long ret, err, i; 276 277 if (maxevents <= 0 || 278 maxevents > (INT_MAX/sizeof(*kbuf)) || 279 maxevents > (INT_MAX/sizeof(*events))) 280 return -EINVAL; 281 if (!access_ok(events, sizeof(*events) * maxevents)) 282 return -EFAULT; 283 kbuf = kmalloc_array(maxevents, sizeof(*kbuf), GFP_KERNEL); 284 if (!kbuf) 285 return -ENOMEM; 286 fs = get_fs(); 287 set_fs(KERNEL_DS); 288 ret = sys_epoll_wait(epfd, kbuf, maxevents, timeout); 289 set_fs(fs); 290 err = 0; 291 for (i = 0; i < ret; i++) { 292 e.events = kbuf[i].events; 293 e.data = kbuf[i].data; 294 err = __copy_to_user(events, &e, sizeof(e)); 295 if (err) 296 break; 297 events++; 298 } 299 kfree(kbuf); 300 return err ? -EFAULT : ret; 301 } 302 #else 303 asmlinkage long sys_oabi_epoll_ctl(int epfd, int op, int fd, 304 struct oabi_epoll_event __user *event) 305 { 306 return -EINVAL; 307 } 308 309 asmlinkage long sys_oabi_epoll_wait(int epfd, 310 struct oabi_epoll_event __user *events, 311 int maxevents, int timeout) 312 { 313 return -EINVAL; 314 } 315 #endif 316 317 struct oabi_sembuf { 318 unsigned short sem_num; 319 short sem_op; 320 short sem_flg; 321 unsigned short __pad; 322 }; 323 324 asmlinkage long sys_oabi_semtimedop(int semid, 325 struct oabi_sembuf __user *tsops, 326 unsigned nsops, 327 const struct old_timespec32 __user *timeout) 328 { 329 struct sembuf *sops; 330 struct old_timespec32 local_timeout; 331 long err; 332 int i; 333 334 if (nsops < 1 || nsops > SEMOPM) 335 return -EINVAL; 336 if (!access_ok(tsops, sizeof(*tsops) * nsops)) 337 return -EFAULT; 338 sops = kmalloc_array(nsops, sizeof(*sops), GFP_KERNEL); 339 if (!sops) 340 return -ENOMEM; 341 err = 0; 342 for (i = 0; i < nsops; i++) { 343 struct oabi_sembuf osb; 344 err |= __copy_from_user(&osb, tsops, sizeof(osb)); 345 sops[i].sem_num = osb.sem_num; 346 sops[i].sem_op = osb.sem_op; 347 sops[i].sem_flg = osb.sem_flg; 348 tsops++; 349 } 350 if (timeout) { 351 /* copy this as well before changing domain protection */ 352 err |= copy_from_user(&local_timeout, timeout, sizeof(*timeout)); 353 timeout = &local_timeout; 354 } 355 if (err) { 356 err = -EFAULT; 357 } else { 358 mm_segment_t fs = get_fs(); 359 set_fs(KERNEL_DS); 360 err = sys_semtimedop_time32(semid, sops, nsops, timeout); 361 set_fs(fs); 362 } 363 kfree(sops); 364 return err; 365 } 366 367 asmlinkage long sys_oabi_semop(int semid, struct oabi_sembuf __user *tsops, 368 unsigned nsops) 369 { 370 return sys_oabi_semtimedop(semid, tsops, nsops, NULL); 371 } 372 373 asmlinkage int sys_oabi_ipc(uint call, int first, int second, int third, 374 void __user *ptr, long fifth) 375 { 376 switch (call & 0xffff) { 377 case SEMOP: 378 return sys_oabi_semtimedop(first, 379 (struct oabi_sembuf __user *)ptr, 380 second, NULL); 381 case SEMTIMEDOP: 382 return sys_oabi_semtimedop(first, 383 (struct oabi_sembuf __user *)ptr, 384 second, 385 (const struct old_timespec32 __user *)fifth); 386 default: 387 return sys_ipc(call, first, second, third, ptr, fifth); 388 } 389 } 390 391 asmlinkage long sys_oabi_bind(int fd, struct sockaddr __user *addr, int addrlen) 392 { 393 sa_family_t sa_family; 394 if (addrlen == 112 && 395 get_user(sa_family, &addr->sa_family) == 0 && 396 sa_family == AF_UNIX) 397 addrlen = 110; 398 return sys_bind(fd, addr, addrlen); 399 } 400 401 asmlinkage long sys_oabi_connect(int fd, struct sockaddr __user *addr, int addrlen) 402 { 403 sa_family_t sa_family; 404 if (addrlen == 112 && 405 get_user(sa_family, &addr->sa_family) == 0 && 406 sa_family == AF_UNIX) 407 addrlen = 110; 408 return sys_connect(fd, addr, addrlen); 409 } 410 411 asmlinkage long sys_oabi_sendto(int fd, void __user *buff, 412 size_t len, unsigned flags, 413 struct sockaddr __user *addr, 414 int addrlen) 415 { 416 sa_family_t sa_family; 417 if (addrlen == 112 && 418 get_user(sa_family, &addr->sa_family) == 0 && 419 sa_family == AF_UNIX) 420 addrlen = 110; 421 return sys_sendto(fd, buff, len, flags, addr, addrlen); 422 } 423 424 asmlinkage long sys_oabi_sendmsg(int fd, struct user_msghdr __user *msg, unsigned flags) 425 { 426 struct sockaddr __user *addr; 427 int msg_namelen; 428 sa_family_t sa_family; 429 if (msg && 430 get_user(msg_namelen, &msg->msg_namelen) == 0 && 431 msg_namelen == 112 && 432 get_user(addr, &msg->msg_name) == 0 && 433 get_user(sa_family, &addr->sa_family) == 0 && 434 sa_family == AF_UNIX) 435 { 436 /* 437 * HACK ALERT: there is a limit to how much backward bending 438 * we should do for what is actually a transitional 439 * compatibility layer. This already has known flaws with 440 * a few ioctls that we don't intend to fix. Therefore 441 * consider this blatent hack as another one... and take care 442 * to run for cover. In most cases it will "just work fine". 443 * If it doesn't, well, tough. 444 */ 445 put_user(110, &msg->msg_namelen); 446 } 447 return sys_sendmsg(fd, msg, flags); 448 } 449 450 asmlinkage long sys_oabi_socketcall(int call, unsigned long __user *args) 451 { 452 unsigned long r = -EFAULT, a[6]; 453 454 switch (call) { 455 case SYS_BIND: 456 if (copy_from_user(a, args, 3 * sizeof(long)) == 0) 457 r = sys_oabi_bind(a[0], (struct sockaddr __user *)a[1], a[2]); 458 break; 459 case SYS_CONNECT: 460 if (copy_from_user(a, args, 3 * sizeof(long)) == 0) 461 r = sys_oabi_connect(a[0], (struct sockaddr __user *)a[1], a[2]); 462 break; 463 case SYS_SENDTO: 464 if (copy_from_user(a, args, 6 * sizeof(long)) == 0) 465 r = sys_oabi_sendto(a[0], (void __user *)a[1], a[2], a[3], 466 (struct sockaddr __user *)a[4], a[5]); 467 break; 468 case SYS_SENDMSG: 469 if (copy_from_user(a, args, 3 * sizeof(long)) == 0) 470 r = sys_oabi_sendmsg(a[0], (struct user_msghdr __user *)a[1], a[2]); 471 break; 472 default: 473 r = sys_socketcall(call, args); 474 } 475 476 return r; 477 } 478